Output driver devices of the type discussed above (sometimes referred to as "smart power" devices) may typically dissipate about one watt during normal operation. However, when an over-current condition begins to occur, the device reacts by going into a current limiting mode in which it may dissipate much more than one watt. The undesirable consequence of this is that the device may require the use of a heat sink because of the relatively high dissipation that can occur during the current limiting mode.
Conventionally, driver circuits are used to apply on-off signals to the output driver device. However, these drive circuits are presently incapable of adequately sensing fault conditions in the output driver device so that precautionary steps can be taken to prevent high levels of power dissipation, at least not without incurring too much expense and without using too many interconnects between the driver circuit and the output device.